Twins Focus the Nature vs. Nurture Mystery

Can "bad genes" destine people to violence and criminality? As a mystery fan, I've never liked that kind of characterization because I want to unravel not only the puzzle of who-done-it but also the why. A genetically predetermined monster just isn't as interesting in terms of motive and plotting. Plus, the "bad genes" theory tends to drift into offensive racial, ethnic and social stereotypes. And, finally, I prefer mystery solutions that deliver justice, and that means supposing free will rather than genetic determinism. Last year, a Boston Globe article by two associate professors of criminal justice approached the controversy head-on, arguing that a genetic basis for crime has not been adequately explored both because scientists do not have the practical or ethical ability to perform randomized controlled trials and because political headwinds cause them to avoid the issue. In the meantime, the best crime-relevant data untangling heritable personality traits (such as aggression) from environmental factors (such as bad parenting) come from identical twin studies. Overall, research finds about 50% of personality traits are heritable and 50% due to environmental factors--so no simple behavior answers from the twins. Perhaps the mystery of genetics-vs.-environment is why twins are an old theme in literature, often using a good one vs. evil one trope. For the curious, here's some mystery fiction with a twin twist: The Thirteenth Tale by Diane Setterfield, where the gothic history of a mysterious family includes the deeply bonded identical twins Adeline (the violent one) and Emmeline (the calm one); John Hart's The Last Child about a 13-year-old boy who embarks on a dangerous quest for his missing twin sister, with help and hindrance from a local detective; The Nightspinners by Lucretia Grindle, in which a teenage girl with a telepathic connection to her brutally murdered twin sister faces an unknown killer; and Lives of the Twins by Rosamond Smith (aka Joyce Carol Oates), the tale of a shallow woman who takes a dangerous path by initiating affairs with identical twin brothers, one gentle and one sadistic, who are estranged by a terrible secret. For more twin-themed books, see https://www.abebooks.com/books/identical-evil-siamese-lamb-niffenegger/twins-in-literature.shtml

Intriguing Mystery Plot Twists, Fictional and Real

Mystery lovers, by their nature, are lovers of the plot twist. Just a few of my favorites with surprise twists include Gone Girl by Gillian Flynn, The Girl on the Train by Paula Hawkins, Shadow of the Wind by Carlos Ruiz Zafon, The Thirteenth Tale by Diane Setterfield, In the Woods by Tana French, Shutter Island by Dennis Lehane, The Secret Keeper by Kate Morton, and We Were Liars by E. Lockhart. Of course, the great Agatha Christie has multiple entries, such as The Murder of Roger Ackroyd, And Then There Were None, Death on the Nile and Murder on the Orient Express. Notice how often the "unreliable narrator" is key to the surprise twist, by the way. Sometimes fact is even more astounding than fiction, however. Just check out Listverse.com's post about 10 real-life mysteries solved by incredible plot twists. For example, there's seven-year-old Maria Ridulph's 1957 murder solved by a "murder will out" twist 54 years later. Although 17-year-old neighbor John Tessier was suspected of Ridulph's murder at the time, he had an iron-clad alibi: He had taken a train trip on the day the child disappeared. The police reopened the case in 1994 after a deathbed statement by Tessier's mother, but the alibi had them stumped--until one of Tessier's ex-girlfriends helpfully provided an old framed photograph. Investigators found the 1957 train ticket hidden inside, unstamped because Tessier had never used it to take the trip. Tessier was finally charged with murder in 2011. Science, not luck, played the key role in another seemingly insoluble murder. After a 13-year-old girl was found stabbed to death in 2011 in Italy, police took 15,000 DNA tests to compare with DNA samples found at the murder scene. One man's near-match led to testing of his family, including a long-dead uncle and the uncle's children--without an exact match. Police then learned the dead uncle had been a very active womanizer, and 500 women were investigated. Police finally found a married woman whose twins turned out to be the secret offspring of the dead uncle. One of the twins was a match for the killer's DNA, and he was charged with murder in 2014. For more real-life twists, read http://listverse.com/2015/03/25/10-mysteries-resolved-by-unbelievable-surprise-twists/.